fix bug import and Device Error args

git-svn-id: https://redmine.imt-atlantique.fr/svn/xaal/code/Python/trunk@1374 b32b6428-25c9-4566-ad07-03861ab6144f

xaal-lib/src/xAAL/devices.py

@@ -23,6 +23,7 @@
 from __future__ import print_function
 
 from . import config
+from . import tools
 
 import logging
 
@@ -80,17 +81,19 @@ class XAALAttribute(object):
 
 class DeviceError(Exception):
 
-    def __init__(self, code, desc):
-        self.code = code
-        self.description = desc
+    def __init__(self, value):
+        self.message = value
+
+    def __str__(self):
+        return repr(self.message)
 
 
 class Device(object):
 
     def __init__(
             self,
-            devtype=None,
-            addr=None,
+            devtype,
+            addr,
             parent=None,
             childrens=None,
             engine=None):